Rib-knitting machine.



R. w. SCOTT.

RIB KNITTING MACHINE.

Ar'rmoumx mum FEB. 9. 1912.

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' R. w. SCOTT.

RIB KNITTING MACHINE.

Patented Aug. 12,1913.

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ROBERT W. SCOTT, 0F BOSTON, MASSACHUSETTS, ASSIGNOB'TO SCOTT & WILLIAMS, INCORPORATED, OF CAMDEN, NEW JERSEY, ACORPORATION OF NEW JERSEY.

RIB-KNITTING macnmn.

Specification Letters Patent.

Patented Aug. 12, 1913,

Application filed February 9, 1912. Serial No. 676,526.

that class of ribbed fabrics in whose production the needles have a primary andsecondary action, the objectof my invention being to insure the positive knocking over of the stitches upon the secondary needles with less strain than usual upon the yarn composing said stitches, my invention having'special value in knitting webs of fine gage and in which light and delicate yarns are employed.

In the accompanying drawings Figuresl and 2 represent on anenlarged scale sufiicient of the parts of a rib knitting machine to illustrate my invention, the views showing the parts in differentpositions; Fig. 3 is a diagrammatic view illustrating certain of the cylinder and dial needles of an ordinary rib knitting machine and showing why the knocking over of the stitches upon the dial or secondary needles is, in such a machine, difiicult of accomplishment; Fig. 4 is a similar view illustrating how the knocking over of the stitches upon the secondary needles is facilitated by my invention; Fig. 4 is a view looking in the direction of the arrow m, Fig. 4; Fig. 5 is a vertical sectional view of part of a rib knitting machine constructed in accordance with my invention; Fig. 6 is an inverted plan view of part of the dial cam cap of the machine; Fig. 7 is an elevation of part of the cylinder cam ring of the machine showing the same disposed in' a flat plane; Fig. 8 is a plan view of part of the dial with needles removed from certain grooves, and both needles and jacks removed from other grooves thereof; Fig. 9 is a vertical sectionalview of part of a rib knitting machine illustrating a modification of my invention, and Fig. 10 is a plan view of part of the same.

In cases where ribbed fabric is formed by primary action of one set of needlesand I secondary action of the other set difficulty is experienced in knocking the old loops carried by the secondary needles over the new loops of yarn which have just been introduced into the hooks of said needles, experience having, demonstrated that this difliculty is not lessened, as at first it might appear to be, when the hook of the secondary needle is made smaller or otherwise altered in shape to facilitate the knocking over of the old loop. The difliculty arises from the fact. that in accordance with the present methods of procedure the attempt is made to force the old loop over the new yarn when the latter has assumed the most unfavorable conformation for permitting the free passage of said old loop. This will be understood on reference to Fig. 3, in which m may be taken to represent the primary orcylinder needles of a rib knitting machine and 3/ may be taken to representthe secondary or dial needles. It =-will be noticed that the yarn w lyin between each dial needle and the adjoining cylinder needles has assumed an angular form, the sides of the triangle being drawn taut as the dial needle is retracted to knock over its old loop, and the more draft that is imparted to the dial needle the tighter will said sides of the triangle be drawn and the more difiicult it will be to force the old loo-p over these triangular bights of yarn.

In all rib knitting machines with which I am familiar, however, this practice is followed, the primary or cylinder needles first drawing their stitches and the intervening yarn being laid over the secondary or dial needles, and the latter being then retracted to *a point where the hook of the'needle is well within the edge of the dial before the knocking over of the old loop, but owingto the angular disposition of the new yarn as before described the old loops tend to hang on the hooks of the dial needles and only partially knock over so that in many instances when the' dial needle is again projected, it pierces the 'old loop and causes tuck,stitches and other faults in the web. This difficulty does not arise in connect-ion with the cylinder or primary needles notwithstanding thefact that the same triangular disposition of the yarn is present, for the reason that the yarn is yielded freely to the cylinder or primary needles from the source ofvsupply, while in the case of a dial needle the yarn is tightly held by the cylinder needle on each side of the same and cannot yield.

die.

I have discovered that when each cylinder or primary needle, after drawing its stitch, is slightly raised again and the old loop is knocked over upon each dial needle when the hook of the latter is but a short distance inside of the circle formed by the backs of the cylinder needles, such knocking over can be readily effected Without any undue strain upon the yarn, since the slack yielded when the needles bear this relation will permit the triangle formerly assumed by the new loop on the dial needle tocollapse and assume, in a general way, the configuration shown in Fig. 4, which, as will be evident, offers no material resistance to the slipping of the old loop from the dial nee- The new loop will not, however, as some the position shown in Fig. 4 until the old loop has been pushed over the hook of the needle and is in position to be drawn down past the same, so as to engage the new loop, the slackness of the latter being such that it otters no material resistance to such action. Before the old loop is pushed out over the hook of the dial needle the new loop will occupy a position approximating that shown in Fi a so that it is possible to push outthe old loop by means of an implement acting solely upon said old loop .where it hangs down below the dial needle, the new loop being free from the action of such implementand hence not being tightened thereby.

By preference, I accomplish the knocking over of the old loops upon the dial needles by placing underneath each of said dial or secondary needles 3 a jack 1 which plays in the same groove as the dial needle and has a butt 2 for engagement with a suitable cam groove 3 in the dial cam cap 4, whereby it can be radially projected and retracted at the proper tunes, such jack having its outer end flattened and widened, as shown at 5 in Fig. 8, so as to occupy the full width of the cutting at the periphery of the needle dial, which cutting is wider than the groove in which the stems of the needle and jack reciprocate, in order to provide yarn room between the dial needle and the walls 6 which intervene between the dial needles at the outer edge of the dial.

The cams 7 which act upon the jacks 1 may be rendered adjustable in any ordinary manner so as to vary the extent of projection of said jacks. The dial needles y have the usual butts 8 which are engaged bysuitable cam elements 9 on the dial cam cap to project and retract said needles. These cams need not be adjustable but should be disposed to so retract the dial needles as to impart less than the usual amount of draft thereto, the hooks of said dial needles, when the latter are fully retracted, being but a short distance within the circle formed by the backs of the cylinder needles. The outer end or nose of the jack 1, when said jack is projected, acts upon the old loop hanging upon the dial needle and forces the same outwardly beyond the hook of the needle so that it can readily knock over the same, as shown in Fig. 2, the widened or spade-like nose of the ack preventing the latter from piercing the old loop when the jack is thus projected.

In Fig. 7 of the drawing, 10 represents the cam conformation of the cylinder cam ring which effects the slight rise of the cylinder needles after they have drawn the primary stitches upon said needles.

In Fig. 9 I have shown an obvious modification of my invention, and it will be evident that other devices may, within the scope of my invention, be employed to cast the old loops from the dial or secondary needles over the slackened loops held in the hooks of said needles.

In the modification shown in Fig. 9 an arm or finger 11 is carried on the central spindle 12 of the machine, the outer end of said finger carrying a knocking over disk 13 which lies just beneath the dial needles and has teeth or bits extending slightly outward beyond the edge of the dial at the knocking over point so as to force the old loops over the hooks of the dial needles with the same effect as the acks 1 shown in the other figures of the drawing. The yarn of the new loops will enter the notches of the disk and will cause the latter to rotate.

If the machine shown in Fig. 9 is one having a stationary cylinder and dial the finger 11 will rotate, and if the machine is one having a rotating cylinder and dial the finger will be held stationary at the knock-ingover point for the dial or secondary needles. In a machine of this type some other means than the usual engaging dogs on the cylinder and dial will be used to lock together these members of the machine. Instead of -maintaining the slack in the new loops on the dial needles by arresting the draft of the latter as soon as their hooks are within the circle of the backs of the cylinder needles, Iv may, in some cases, adopt a reverse procedure by imparting-full draft to the dial needles and permitting the raised cylinder needles to yield inwardly or follow the movement of the dial needles during the final portion of their draft, in which case the outer edge of the dial will constitute the means for knocking over the old loops on the dial needles, the slack in the new loops, however, bein maintained by the inward movement of t e upper ends of the cylinder needles while such knocking over of the old loops is being eflected. Mechanism for accomplishing such radial movement of the cylinder needles in their grooves is well known, eifective mechanism for this purpose being shown, for instance, in the patent of J. M. Merrow No: 291,777 dated January 1,1884.

In machines of extremely fine gage the widening of the stitch engaging end of the jack may be omitted,-the* main purpose of the invention being to cause said jack to act upon the depending portion of the old. stitch hanging upon the needle without imparting tension to the new loop by acting upon the depending portions of the yarn which forms said new loop.

I claim 1. A rib knitting machine comprising knitting instrumentalities including two sets of needles and their carriers, means for slackening the new, loops of yarn upon one set of needles, and means operating free from contact with said new loops to knock the old loops over the same while said new loops remain. slackened.

2. A rib knitting machine. comprising knitting instrumentalities including. two

sets of needles and their carriers, and means extensible beyond the edge of the carrier for one set of needles and operating free from contact with the new loops on said needles to knock over the old loops upon said needles.

,3. A rib knitting ting instrumentalitles including two sets of needles and carriers therefor, means for retracting the needles of one set soth'at their hooks will remain outwardly beyond the edge of their carrier, and means operating free from contact with the new loops on said machine having knitneedles to knock over the loops on saidneedles.

4. The combination in a rib knitting machine of knitting instrumental-ltles including two sets of needles, means for actuating one set as primary needles and the other set as secondary needles, means for slackening the loops of new yarn upon the needles of the secondary set and maintaining them in such slackened condition while the old loops are being knocked over and means operating free from contact with the new loops for effecting such knocking over.

5. The combination; in a rib knitting machine, of knitting needles, knocking-over jacks disposed at the backs of the needles with which they cooperate, an-d'means for operating said knitting needles and knocking-over jacks independently, whereby the 1acks serve. to knock over the stitches in 

